This is a 40-frame panorama capturing a newly wedded couple exploring the ancient Pinnacles Desert under the pristine West-Australian night sky. It took 17 minutes to capture the entire image and a very brave couple to endure the 12 degree coastal breeze in their summer wedding dress. As a whole, the image looks complicated to capture and, to and extent, that is true. But if you break it down into a methodical workflow, capturing this image might be easier than it seems.
Capturing the Image
This image started to take shape when a mate of mine, Ashley Lam, asked me to be the photographer for his wedding. He asked that I not only document the wedding, but also do an Astro-Wedding shot for their wedding photo at a later time. I couldn't say no to the request and started thinking about some locations and compositions. Having traveled along the western coast of Australia quite a bit, I picked out two suitable locations in consideration of the logistics of the shoot. We had to take into account that we had to be in a suitably dark location (typically 1.5 - 2 hrs out of the city), and that both the bride and groom would be wearing their wedding attires which could possibly hinder movement, thus ruling out uneven terrain. I ended picking either the Lancelin Sand Dunes or the Pinnacles Desert, both around 2 hrs North of Perth, both with easy access using any vehicle. The couple decided on the Pinnacles.
As the Milky Way season starts to peak from the month of May, the core rises earlier on in the night and reaches my desired elevation for the composition at around 9:30pm. The couple arrived at the location at 8pm to do some practice and test shots. I got them to stand in the right pose and angled both their bodies 45 degrees to the left with their backs towards the camera. Put their weight on their left leg and slightly lean forward, and point the heal of their right foot towards the sky. Tilt their heads upwards and stretch their arms out at 45 degrees. This would give an illusion that they are "leaning into the picture". The groom would be tasked with holding the light. We practiced holding the pose for a while until it was time to shoot.
When the Milky Way had reached the right elevation, I lead them to a spot I had picked out before they arrived and asked them to stand there while I set up my camera equipment.
For this shoot, I used a Nikon D750 DSLR equipped with an Optolong L-Pro light pollution filter and Nikon 20mm f1.8G lens. For the camera support, I used a Gigapan Epic Pro panorama mount and a Monoprice Carbon Fiber tripod. Using this set up, it would take 17 minutes to capture an entire photosphere with a 20 second exposure and a 40% overlap between the 40 frames in an 5 row by 8 column grid pattern.
I also used a Yong Nuo 565EX speedlight equipped with a Gary Fong Lightsphere and Yong Nuo RF603N ii Wireless transmitters for the wireless lighting.
Shot settings used were ISO 3200, F2.2 and 20 seconds shutter speed.
For the first half the shot, the camera was capturing the sky and the couple were free to soak in the view of the Milky Way. After 8 minutes, I asked them to get ready and I turned on the wireless transmitters to trigger the flash to illuminate the scene. For the next 2 exposures, the groom had to lift the speedlight up at the start of the exposure before it fires and then relax his arm again. This was so he could keep up his strength before needing to hold the pose properly. After the 2 frames, I ran towards them and collected their jackets and other insulation clothing and told them to hold the pose for the next 3 frames which they would appear in. I ran back to the camera and continued to shoot. Once those 3 frames were completed, I handed them their jackets back, by which time they were feeling pretty damn cold. The couple still had to stand in position while the camera captured the rest of the foreground while the groom lifted the speedlight up at the start of every exposure to keep the shadows consistent between frames.
All in all, the couple stood totally still for about 65 seconds out of the 17 minutes.
We shot another 2 panoramas before calling it a night at about 11pm, and then a 2 and a half hour drive home. Being quite an experienced when it comes to driving on the coastal road at night, I took point and lead the couple back towards the city, lighting up the way with a 9000 Lumen driving light ( I counted 7 kangeroos and 1 owl on the drive home that night).
RAW File Preparation
Upon returning home at about 1:30am, I downloaded the RAW files off my SD card and loaded them up into Adobe Lightroom for inspection and preparation. I have done astrophotography sessions at the Pinnacles multiple times before but never with a light pollution filter. I used the Optolong L-Pro filter for this shoot and wanted to see the effects of the filter.
What I like:
- The L-Pro filter sits inside the mirror chamber, out of the way and filters the already corrected light that has passed through the lens instead of being filtered before corrected in a traditional screw mount filter.
- It's sharp. There is no perceivable difference in sharpness when using the L-Pro compared to not using it.
- It works as described. The filter works by attenuating the undesirable parts of the light spectrum emitted by sodium vapour lights. It also increases the contrast of the Milky Way and other celestial objects, bringing out the vivid colours of night sky.
- It's not limited to a single lens thread size as it sits inside the camera.
What I dislike:
- You lose about 2/3 stops of light and have to compensate with a larger aperture or longer shutter speed.
- Clumsy installation. It's not that bad once you're used to installing and removing the filter, but my initial attempts to install it were quite frustrating having not known the correct technique to install it. Once I figured it out, installing it became a 20 second job.
- Flaring issues. I'm not sure if it's just because of the speedlight I used, but I did notice several green flare marks in the RAW files which I've never seen before using the D750 and 20mm 1.8G combo before. I suspect that the flaring comes from internal reflections in the mirror chamber.
Initial inspection of the RAW files showed that they were sharp and in focus. The Milky Way looked good straight out of camera and the lighting between the foreground frames looked consistent enough to stitch. I did my pre-stitch RAW file preparation in Lightroom which included adjusting:
- Colour Profile: Change from Adobe Colour to Camera Neutral
- Lens Correction: Remove Chromatic Aberration and Enable Lens Profile Correction
- Adjust White Balance
- Basic Adjustments: White and Black sliders
- Add Clarity, Vibrance and Saturation
- 'S' curve applied to the Tone Curve
With these adjustments made, the RAW files were exported as 16bit TIFF files, ready to be stitched. Each TIFF file came up to 120mb. All 40 frames together came up to 4.8Gb worth of data.
Once the RAW files had been exported as TIFF files, the images were imported to Autopano Giga, my stitch software of choice. Using the Gigapan plugin, I synced the shoot layout and overlap amount within Autopano Giga to aide in the stitching process. Selecting the right settings in Autopano will relieve some stress on the stitching algorithm which will result in a more efficient workflow.
After the TIFF files are stitched together, you get an initial projection of what the final image would look like. Being a 360 photosphere, we have the opportunity to decide what type of projections type we would like to use and we also have the ability to mildly recompose the shot after the fact. For ultra-wide angle panoramas, I prefer to use a "Stereographic" projection which maintains straight lines and is able to project around 270 degrees without major distortion. There are also other projection types like Spherical, Mercator and Little World. Each of these projection types have their uses, but the case of an ultra-wide panorama, Stereographic projections work best. I re-position the image to get the desired composition and crop it down to a usable aspect ratio.
Because of the way the frames are overlapped, that couple will appear in multiple frames. I want to force Autopano to use the image of the couple posing from one particular frame where they are holding the pose the best, while masking them out in the other frames they appear in. This will ensure that no stitch errors will occur at the most critical part of the final image.
I render out the stitched image as a 16bit TIFF file. The final megapixel count is above 220MP for this image. The megapixel count will depend greatly on the focal length and sensor pixel density. The stitched image is then imported into Lightroom for processing.
Processing the Final Image
I generally process my milky way photos to taste rather than scientific accuracy. I prefer a high-contrast dramatic look and this can be achieved be finely adjusting the Tone-Curve and using Graduated Filters. As for the colour balance, I prefer a neutral look leaning slightly towards magenta.
Understanding the capabilities of your camera sensor is advantageous when it comes to editing the files it produces. Some camera sensors have more dynamic range than others while some have less colour noise and grain. These factors will limit the amount of processing the stitched file could take before breaking or become visually unacceptable. The D750 is a near ISO invariant camera which allows the ISO to be raised after the image is captured by lifting the exposure in post production. This allows me to capture more highlight data while selectively raising the shadow areas to keep noise to a minimum. As such, the sky of this image is essentially at ISO3200 while the foreground is closer to ISO8000. I tend to use heavy vignettes as well to add to the dramatic look.
Once I am satisfied with the Lightroom edit, the image is then imported into Photoshop for some finishing touches such as removing any unwanted artifacts like lens flare and minor stitch marks, and applying a "Bloom" effect, a contrast-enhancing editing technique inspired from character model lighting in video games (more on this topic in a future article).
The process of capturing a wide field panorama of the night sky can be lengthy and tiresome, but extremely rewarding. The reality is that Nightscape Astrophotography is a very challenging genre of photography and requires a lot of planning, research, study and a hell lot of luck.
Overall, I am quite pleased with the results of this shoot. It's great to see the final image take shape after having the composition in my head for so long. It's definitely one of my more memorable astrophotography adventures.